W3C home > Mailing lists > Public > www-rdf-dspace@w3.org > June 2004

Re: Fwd: [MODS] MADS: XML schema for authorities

From: Stefano Mazzocchi <stefano@apache.org>
Date: Mon, 07 Jun 2004 17:36:49 +0200
Message-ID: <40C48B91.8000201@apache.org>
To: "Butler, Mark" <mark-h.butler@hp.com>
Cc: simile general <www-rdf-dspace@w3.org>
Butler, Mark wrote:
>>Converting this schema to a useful RDF is algorithmically impossible 
>>since too much information is kept implicit and/or optional.
> I don't think its impossible - for example of how to do it, see the enclosed
> XSLT stylesheet which demonstrates how to convert the examples. 
> Writing XML in this way is quite a useful design pattern for getting
> RDF-like extensibility in XML while retaining compatibility with things like
> WSDL based web services, where we have to write an XML Schema to describe
> our data. Writing such a schema limits our ability to add extensions, so one
> way to overcome this is to use attributes to encode property names, as this
> frees us from the schema constraint. Of course once we are free of the
> schema constraint, then we lose our ability to validate, but then that's a
> problem we have with RDF as well. 

Very true.

The problem I have is not about the encoding of the semantics in the 
attributes, but the fact that those attributes are optional.

For example, in your stylesheet you write:

<xsl:template match="ref">
     <xsl:element name="{@relatedType}" 
         <xsl:when test="geographic">
         <xsl:when test="topic">

but in the MADS schema you get

   <xsd:attribute name="relatedType" use="optional">

so, if the attribute is not present, the XML is legal, but the 
stylesheet wouldn't work.


Received on Monday, 7 June 2004 11:36:56 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:13:11 UTC